Polarizing element, method of manufacturing polarizing element, and electronic apparatus

ABSTRACT

A polarizing element includes: a substrate; a plurality of reflection layers that is arranged in a band shape at a predetermined interval on the substrate; dielectric layers that are formed on the reflection layers; and inorganic micro-particle layers that are formed on the dielectric layers by inorganic micro-particles having shape anisotropy in which a length of a diameter of the micro-particles in an arrangement direction of the reflection layers is longer than a length of a diameter of the micro-particles in a direction orthogonal to the arrangement direction of the reflection layers and has convex portions toward a side of a first adjacent reflection layer and a side of a second adjacent reflection layer.

BACKGROUND

1. Technical Field

The present invention relates to a polarizing element, a method ofmanufacturing a polarizing element, and an electronic apparatus.

2. Related Art

Liquid crystal projectors as electronic apparatuses include liquidcrystal devices as optical modulation devices. The liquid crystal devicehaving a configuration in which a liquid crystal layer is pinchedbetween one pair of substrates disposed to oppose each other is known.On one pair of the substrates described above, electrodes used forapplying voltages to the liquid crystal layer are formed. In addition,on the outer sides of the substrates, an incident-side polarizingelement and an outgoing-side polarizing element are disposed. Thus,predetermined polarized light is configured to be incident to andoutgoing from the liquid crystal layer. Meanwhile, in order to acquire ablack projection image in the above-described liquid crystal projector,almost all the light energy needs to be absorbed by the outgoing-sidepolarizing element. Thus, particularly, an increase in the temperatureof the outgoing-side polarizing element is marked. Accordingly, forexample, a technique in which two polarizing elements are disposed onthe outgoing side, most of the light energy is absorbed by an outgoingpre-polarizing element disposed right after the liquid crystal device,and the contrast of a projection image is improved by an outgoing mainpolarizing element disposed on the latter stage is known. In order toacquire a higher heat-resistance property, the polarizing element isformed from an inorganic material. The polarizing element includes asubstrate, reflection layers formed on the substrate, dielectric layersformed on the reflection layers, and inorganic micro-particle layersformed on the dielectric layers (for example, see JP-A-2008-216957).

However, when the polarizing element is used as an outgoingpre-polarizing element, depending on the form of disposition of theinorganic micro-particle layer, optical activity is given to theoutgoing light. As a result, there are problems in that the intensity ofleakage light leaking from the outgoing main polarizing elementincreases, and the contrast of the liquid crystal projector isdecreased.

SUMMARY

An advantage of some aspects of the invention is to solve at least apart of the problems described above and the invention can beimplemented in the following forms or application examples.

APPLICATION EXAMPLE 1

According to this application example, there is provided a polarizingelement including: a substrate; a plurality of reflection layers that isarranged in a band shape at a predetermined interval on the substrate;dielectric layers that are formed on the reflection layers; andinorganic micro-particle layers that are formed on the dielectric layersby inorganic micro-particles having shape anisotropy in which a lengthof a diameter of the micro-particles in an arrangement direction of thereflection layers is longer than a length of a diameter of themicro-particles in a direction orthogonal to the arrangement directionof the reflection layers and has convex portions toward a side of afirst adjacent reflection layer adjacent of one reflection layer and aside of a second adjacent reflection layer adjacent of the onereflection layer.

According to such a configuration, the inorganic micro-particle layer isformed from inorganic micro-particles having shape anisotropy.Accordingly, the absorbability of light can be further increased.Furthermore, the inorganic micro-particle layer has convex portionstoward one adjacent reflection layer side and the other reflection layerside, that is, toward different directions (two directions).Accordingly, the intensity of leakage light can be decreased bydecreasing the optical activity of the inclined incident light.

APPLICATION EXAMPLE 2

The polarizing element according to the above-described applicationexample may be configured such that the inorganic micro-particle layerhas a first inorganic micro-particle layer that has a first convexportion disposed on the side of the first adjacent reflection layer anda second inorganic micro-particle layer that has a second convex portiondisposed on the side of the second adjacent reflection layer.

According to such a configuration, the optical activity of the inclinedincident light is decreased by the first and second convex portions ofthe inorganic micro-particle layer. Accordingly, the intensity ofleakage light can be decreased.

APPLICATION EXAMPLE 3

The polarizing element according to the above-described applicationexample may be configured such that, in the cross-sectional vieworthogonal to the arrangement direction of the reflection layers, theratio between cross-sectional areas of the first inorganicmicro-particle layer and the second inorganic micro-particle layer isequal.

According to such a configuration, since the ratio between thecross-sectional areas of the first inorganic micro-particle layer andthe second inorganic micro-particle layer is equal, optical activity ofthe inclined incident light due to balanced configuration of theinorganic micro-particle layers can be efficiently decreased.

APPLICATION EXAMPLE 4

According to this application example, there is provided a method ofmanufacturing a polarizing element. The method includes: forming aplurality of reflection layers that is arranged in a band shape at apredetermined interval on a substrate; forming dielectric layers on thereflection layers; and forming inorganic micro-particles having shapeanisotropy in which a length of a diameter of the micro-particles in thearrangement direction of the reflection layers is longer than a lengthof a diameter of the micro-particles in a direction orthogonal to thearrangement direction of the reflection layers on the dielectric layersand forming inorganic micro-particle layers that have convex portionstoward a side of a first adjacent reflection layer adjacent of onereflection layer and a side of a second adjacent reflection layeradjacent of the one reflection layer.

According to such a configuration, since the inorganic micro-particlelayer is formed from inorganic micro-particles having shape anisotropy,the absorbability of light can be further increased. In addition, theinorganic micro-particle layer has convex portions toward one adjacentreflection layer side and the other reflection layer side, that is,toward different directions (two directions). Accordingly, the intensityof leakage light can be decreased by decreasing the optical activity ofthe inclined incident light.

APPLICATION EXAMPLE 5

The method of manufacturing a polarizing element according to theabove-described application example may be configured such that theforming of inorganic micro-particle layers includes: forming a firstinorganic micro-particle layer having a first convex portion that isobliquely directed to the side of the first adjacent reflection layer byobliquely forming a film from the side of the first adjacent reflectionlayer; and forming a second inorganic micro-particle layer having asecond convex portion obliquely directed to the side of the secondadjacent reflection layer by obliquely forming a film from the side ofthe second adjacent reflection layer.

According to such a configuration, the optical activity of the inclinedincident light is decreased due to the first convex portion and thesecond convex portion of the inorganic micro-particle layer, whereby theintensity of leakage light can be decreased.

APPLICATION EXAMPLE 6

According to this application example, there is provided an electronicapparatus including the above-described polarizing element or apolarizing element that is manufactured by using the above-describedmethod.

According to such a configuration, an electronic apparatus that hassuperior optical characteristics can be provided. Particularly, when thepolarizing element is used as an outgoing pre-polarizing element of aliquid crystal projector, the optical activity of outgoing light isdecreased. Accordingly, the intensity of leakage light leaking from theoutgoing main polarizing element is decreased, whereby the contrast ofthe liquid crystal projector can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIGS. 1A to 1C are schematic diagrams showing the configuration of apolarizing element.

FIGS. 2A and 2B are explanatory diagrams showing the forms of apolarizing element and the characteristics of the intensity of leakagelight.

FIGS. 3C and 3D are explanatory diagrams showing the forms andcharacteristics of the intensity of leakage light of a polarizingelement.

FIGS. 4A to 4E are process drawings showing a method of manufacturing apolarizing element.

FIG. 5 is a schematic diagram showing the configuration of a liquidcrystal projector as an electronic apparatus.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the invention will be described withreference to the drawings. In order to allow each member which is shownin the drawings to have a size which allows them to be recognized, themembers are depicted using different scales.

Configuration of Polarizing Element

First, the configuration of a polarizing element will be described.FIGS. 1A to 1C show the configuration of the polarizing element. FIG. 1Ais a plan view, FIG. 1B is a cross-sectional view, and FIG. 1C is anenlarged partial view. As shown in FIGS. 1A to 1C, the polarizingelement 1 includes: a substrate 2; a plurality of reflection layers 3arranged in a band shape at a predetermined interval on the substrate 2;a dielectric layer 4 that is formed on the reflection layer 3; and aninorganic micro-particle layer 5 that is formed on the dielectric layer4 by inorganic micro-particles 50 a having shape anisotropy in which thelength La of the diameter of micro-particles in the arrangementdirection of the reflection layer 3 is longer than the length Lb of thediameter of the micro-particles in the direction orthogonal to thearrangement direction and has convex portions toward one adjacentreflection layer 3 side and the other adjacent reflection layer 3 side.In the description below, an XYZ coordinate system is set, and thepositional relationship of members will be described with reference tothe XYZ coordinate system. Here, a predetermined direction within ahorizontal plane is set as the X axis direction, a direction orthogonalto the X axis direction within the horizontal plane is set as the Y axisdirection, an a direction that is orthogonal to the X axis direction andthe Y axis direction within a vertical plane is set as the Z axisdirection. In this embodiment, the extension direction of the reflectionlayer 3 to be described later is denoted by the Y axis direction, andthe axis of the arrangement of the reflection layer 3 is denoted by theX axis direction.

The substrate 2 is formed from a material that is transparent to abandwidth of light used (in this embodiment, the visible-light range),for example, a material such as glass, quartz, sapphire, crystal, orplastic having translucency. There is a case where the polarizingelement 1 stores heat so as to be at a high temperature depending on theuse of the polarizing element 1. Accordingly, it is preferable to useglass, quartz, sapphire, or crystal that has high heat resistance as thematerial of the substrate 2.

On one face side of the substrate 2, as shown in FIG. 1A, the pluralityof reflection layers 3, which extends in the Y axis direction, is formedin a stripe-like shape (band shape) in the plan view. As the material ofthe reflection layer 3, a light reflecting material that has arelatively high light reflectivity such as aluminum (Al) is used. Inaddition, other than aluminum, metal or a semiconductor material such assilver, gold, copper, molybdenum, chrome, titanium, nickel, tungsten,iron, silicon, germanium, or tellurium can be used.

The reflection layers 3 are formed at the same interval in the X axisdirection with a period less than the wavelength of the visible-lightrange. In addition, a groove portion 7 is formed between the reflectionlayers 3 that are adjacent to each other. For example, the height of thereflection layer 3 is in the range of 20 nm to 200 nm, and the width ofthe reflection layer 3 is in the range of 20 nm to 70 nm. In addition,the interval (the width of the groove portion 7 in the X axis direction)of adjacent reflection layers 3 is in the range of 80 nm to 130 nm, andthe period (pitch) thereof is 150 nm. As above, the reflection layers 3of the polarizing element 1 have a wire grid structure. The reflectionlayers 3 allow linearly polarized light (a TM wave) that oscillates in adirection (the X axis direction) approximately orthogonal to theextension direction of the reflection layer 3 to be transmitted byreflecting (attenuating) linearly polarized light (a TE wave) thatoscillates in a direction approximately parallel to the extensiondirection of the reflection layer 3 (the Y axis direction).

The dielectric layer 4 is formed from an optical material such as SiO₂,which is formed as a film by using a sputtering method or a sol-gelmethod (for example, a method in which the reflection layer coated withsol, for example, by using a spin coat method, and the sol is formed asgel through thermal curing), transparent to visible light. Thedielectric layer 4 is formed as an underlying layer of the inorganicmicro-particle layer 5. In addition, the dielectric layer 4 is formed soas to increase the interference effect by adjusting the phase ofpolarized light that is transmitted through the inorganic micro-particlelayer 5 and is reflected by the reflection layer 3 with respect to thepolarized light reflected by the inorganic micro-particle layer 5.

As the material composing the dielectric layer 4, a general materialother than SiO₂ such as Al₂O₃ or MgF₂ can be used. These materials canbe formed as a thin film by using a general vacuum film forming methodsuch as a sputtering method, a vapor-phase epitaxial method, or a vapordeposition method or by coating the upper side of the substrate 2 with asol-state material and thermally curing the substrate 2. It ispreferable that the refractive index of the dielectric layer 4 is higherthan 1 and equal to or lower than 2.5. Since the optical characteristicsof the inorganic micro-particle layer 4 are influenced by the refractiveindex of the surroundings thereof, the characteristics of the polarizingelement can be controlled by using the material of the dielectric layer.

The inorganic micro-particle layer 5 is formed on the dielectric layer4. In this embodiment, as shown in FIG. 1B, the inorganic micro-particlelayer 5 is formed on the top of the dielectric layer 4.

The inorganic micro-particle layer 5 is formed by inorganicmicro-particles 50 a. The inorganic micro-particle 50 a, as shown inFIG. 1C has shape anisotropy in which the length La of the diameter ofthe micro-particle in the arrangement direction (the Y axis direction)of the reflection layer 3 is longer than the length Lb of the diameterof the micro-particle in a direction (the X axis direction) orthogonalto the arrangement direction (the Y axis direction) of the reflectionlayer 3. As above, since the inorganic micro-particle has shapeanisotropy, the optical constants in the Y-axis direction (the long-axisdirection) and the X-axis direction (the short-axis direction) can beset to be different from each other. As a result, specific polarizationcharacteristics of absorbing a polarized component that is parallel tothe long-axis direction and transmitting a polarized component that isparallel to the short axis direction can be acquired. The inorganicmicro-particle layer 5 that is composed of the inorganic micro-particles50 a having shape anisotropy as above can be formed by orthorhombic filmforming such as oblique sputtering film forming.

As the material of the inorganic micro-particle 50 a, an appropriatematerial is selected in accordance with the bandwidth used as thepolarizing element 1. In other words, a metal material or asemiconductor material satisfies such a condition. More specifically, asexamples of the metal material, there are simple substances of Al, Ag,Cu, Au, Mo, Cr, Ti, W, Ni, Fe, Si, Ge, Te, and Sn or alloys thereof. Inaddition, as examples of the semiconductor material, there are Si, Ge,and Te. Furthermore, a silicide-based material such as FeSi₂(particularly, β-FeSi₂), MgSi₂, NiSi₂, BaSi₂, CrSi₂, or CoSi₂ isappropriately used. In particular, by using an aluminum-based metalmicro-particle formed from aluminum or an alloy of aluminum or asemiconductor micro-particle containing beta iron silicide, germanium,or tellurium as the material of the inorganic micro-particle 50 a, highcontrast (a high extinction ratio) can be acquired for the visible-lightrange. In addition, in order to implement a polarization property for awavelength bandwidth other than that of visible light, for example, aninfrared range, it is appropriate to use micro-particles of Ag (silver),Cu (copper), or Au (Gold) as the inorganic micro-particles composing theinorganic micro-particle layer. The reason for this is that theresonance wavelength of the above-described metal in the long axisdirection is near the infrared range. In addition, other than theabove-described materials, a material such as molybdenum, chrome,titanium, tungsten, nickel, iron, or silicon can be used in accordancewith the bandwidth used.

In the inorganic micro-particle layer 5, in the cross-sectional view(the cross-sectional view in the X axis direction) orthogonal to thearrangement direction (the Y-axis direction) of the reflection layer 3,convex portions are formed toward one adjacent reflection layer side andthe other adjacent reflection layer 3 side. In this embodiment, theinorganic micro-particle layer 5 includes the first inorganicmicro-particle layer 5 a having the first convex portion 10 a that isdisposed on one adjacent reflection layer 3 side and the secondinorganic micro-particle layer 5 b having the second convex portion 10 bthat is disposed on the other adjacent reflection layer 3 side. In otherwords, as shown in FIG. 1B, in the arrangement direction (the Y-axisdirection) in which one reflection layer 3 is formed, the firstinorganic micro-particle layer 5 a and the second inorganicmicro-particle layer 5 b are formed on the positive side of the X axisand the negative side of the X axis. In addition, in this embodiment, inthe cross-sectional view orthogonal to the arrangement direction of thereflection layer 3, when a center line that divides the reflection layer3 into two in the vertical direction with respect to the substrate 2 isdrawn, the ratio between the cross-sectional areas of the first andsecond inorganic micro-particle layers 5 a and 5 b is formed to bealmost equal.

On the inorganic micro-particle layer 5, a protection layer 6 is formed.As the material of the protection layer 6, a general material such asSiO₂, Al₂O₃, or MgF₂ can be used. These materials can be formed as athin film by using a general vacuum film forming method such as asputtering method, a vapor-phase epitaxial method, or a vapor depositionmethod or by coating the upper side of the substrate 2 with a sol-statematerial and thermally curing the substrate 2.

Thus, the polarizing element 1 according to this embodiment includes:the substrate 2 that is transparent to visible light; the reflectionlayers 3, in which band-shaped thin films extending in one direction onthe substrate 2 are disposed at a predetermined interval, that is formedfrom metal; the dielectric layer 4 that is formed on the reflectionlayer 3; and the inorganic micro-particle layer 5 in which the inorganicmicro-particles 50 a are arranged in a linear shape. In addition, theinorganic micro-particle layer 5 is formed so as to be arranged on thedielectric layer 4 in a position corresponding to the band-shaped thinfilm. Furthermore, a wire grid structure is formed having a longitudinaldirection that is the same as the direction in which the inorganicmicro-particles 50 a are arranged in a linear shape, and the inorganicmicro-particle 50 a has shape anisotropy in which the diameter in thearrangement direction of the inorganic micro-particle 50 a is long andthe diameter in the direction orthogonal to the arrangement direction isshort. In addition, the inorganic micro-particle layer 5 has the convexportions 10 a and 10 b toward one adjacent reflection layer 3 side andthe other adjacent reflection layer 3 side.

Here, the relationship between the forms of the first and secondinorganic micro-particle layers 5 a and 5 b and the intensity of leakagelight leaking from an outgoing main polarizing element in a case wherethe polarizing element 1 is used as an outgoing pre-polarizing elementwill be described. FIGS. 2A and 2B are explanatory diagrams showing theform of the polarizing element and the characteristics of the intensityof leakage light.

FIG. 2A shows models of the polarizing element so as to acquire thecharacteristics of the intensity of leakage light through simulation. Inthis simulation, four models including the first to fourth models Ml toM4 shown in parts (a-1) to (a-4) of FIG. 2A are used. The ratio betweenthe cross-sectional areas of the first inorganic micro-particle layer 5a and the second inorganic micro-particle layer 5 b is changed for thefirst to fourth models. In addition, in this simulation, the width ofthe reflection layer 3 is configured as 45 nm, the height of thereflection layer 3 is configured as 60 nm, and the thickness of thedielectric layer 4 is configured as 10 nm. The period is configured as150 nm. In addition, the materials of the substrate 2, the reflectionlayer 3, the dielectric layer 4, and the inorganic micro-particle layer5 are configured as SiO₂, aluminum, SiO₂, and amorphous silicon.

Hereinafter, the characteristic parts of the first to fourth models M1to M4 will be described. First, in the first model M1, as shown in thepart (a-1) of FIG. 2A, the ratio between the cross-sectional areas ofthe second inorganic micro-particle layer 5 b and the first inorganicmicro-particle layer 5 a, in the cross-sectional view in the directionorthogonal to the arrangement direction of the reflection layer 3, isconfigured to be 5:5 with respect to a virtual center line. In otherwords, in the first model M1, the ratio between the cross-sectionalareas of the first inorganic micro-particle layer 5 a and the secondinorganic micro-particle layer 5 b are equal. Similarly, in the secondmodel M2, as shown in the part (a-2) of FIG. 2A, the ratio betweencross-sectional areas of the second inorganic micro-particle layer 5 band the first inorganic micro-particle layer 5 a is 3:7. In the thirdmodel M3, as shown in the part (a-3) of FIG. 2A, the ratio between thecross-sectional areas of the second inorganic micro-particle layer 5 band the first inorganic micro-particle layer 5 a is 1:9. In addition, inthe fourth model M4, as shown in the part (a-4) of FIG. 2A, the ratiobetween the cross-sectional areas of the second inorganic micro-particlelayer 5 b and the first inorganic micro-particle layer 5 a is 0:10. Inother words, in the fourth model M4, a state is formed in which there isno second inorganic micro-particle layer 5 b.

FIG. 2B shows the disposition of simulation models of polarizingelements that include the first to fourth models M1 to M4. As shown inFIG. 2B, an incident-side polarizing element 200 a is disposed on theincident side of light so as to be orthogonal to the optical axis L ofthe incident light, and an outgoing main polarizing element 200 b isdisposed on the outgoing side of the light so as to be orthogonal to theoptical axis L of the incident light. The incident-side polarizingelement 200 a and the outgoing main polarizing element 200 b are assumedto be ideal absorption-type polarizing elements and are maintained to bein a crossed-Nicol state. Between the incident-side polarizing element200 a and the outgoing main polarizing element 200 b, the first tofourth models M1 to M4 are disposed as the outgoing pre-polarizingelements. Here, the first to fourth models M1 to M4 maintain to be in aparallel Nicole state with the outgoing main polarizing element 200 b.In this simulation, in consideration of illumination light of a liquidcrystal projector, the inclined incident light is defined to have a tiltangle θ and a rotation angle φ with respect to the optical axis L. Inaddition, in an actual liquid crystal projector, although a liquidcrystal device is disposed between the incident-side polarizing element200 a and the first to fourth models M1 to M4 as the outgoingpre-polarizing elements, in order to clarify only the characteristics ofthe first to fourth models M1 to M4 as the outgoing pre-polarizingelements, a liquid crystal device is omitted in this simulation. [00401FIG. 3C shows relative values of the intensities of leakage lightleaking from the outgoing main polarizing elements 200 b in the first tofourth models M1 to M4. In this calculation, θ=5° and φ is changed inthe range of 0° to 345° by 15° each time, and a sum thereof is acquired.According to this simulation, the second model M2 (the ratio of thecross-sectional areas of 3:7) has an intensity of leakage light that isabout 4.3 times that of the first model M1 (the second inorganicmicro-particle layer 5 b: the first inorganic micro-particle layer 5a=the ratio of cross-sectional areas of 5:5), the third model M3 (theratio of the cross-sectional areas of 1:9) has an intensity of leakagelight that is about 10.7 times that of the first model M1, and thefourth model M4 (the ratio of the cross-sectional areas of 0:10) has anintensity of leakage light that is about 11.8 times that of the firstmodel M1. In other words, according to this embodiment, it can beunderstood that there is an effect of decreasing the intensity ofleakage light in a case where at least a tiny second inorganicmicro-particle layer 5 b is formed, and a case where the ratio betweenthe cross-sectional areas of the first inorganic micro-particle layer 5a and the second inorganic micro-particle layer 5 b is equal (5:5,horizontally symmetric) is appropriate for decreasing the intensity ofleakage light. FIG. 3D shows the intensities of outgoing light outgoingfrom the outgoing main polarizing element 200 b at the rotation anglewith respect to the optical axis L for the models M1 to M4. In thefigure, φ=0° or 180° is within the X-Z plane in the coordinate systemshown in FIGS. 1A to 1C. Here, φ=0° corresponds to incident light thatis incident from the second inorganic micro-particle layer 5 b side, andφ=180° corresponds to incident light that is incident from the firstinorganic micro-particle layer 5 a side. As shown in FIG. 3D, it can beunderstood that the intensity distributions in the first to fourthquadrants are almost the same in the first model M1. This intensitydistribution is the same as that of the state in which idealabsorption-type polarizing elements are disposed in the crossed-Nicol,and it can be understood that optical activity does not occur in thefirst model M1. On the other hand, for the second models M2 to thefourth models M4, it can be understood that the symmetry between thefirst quadrant and the second quadrant and between the third quadrantand the fourth quadrant collapses so as to further increase theintensity of leakage light. The reason for this, as can be understoodfrom FIG. 2A, is thought to be the inclination of the optical axis fromthe Z-axis direction within the cross-section so as to increase theoptical activity of the inclined incident light due to collapse of thehorizontal symmetry in the structure.

In addition, other than the simulation of the inclined incident lightwith θ=5°, simulation is performed in a similar manner for inclinedincident light with θ=10° and θ=20°. Based on the simulation, as above,by forming the second inorganic micro-particle layer 5 b in addition tothe first inorganic micro-particle layer 5 a, the effect of decreasingthe intensity of leakage light is acquired. In addition, in a case wherethe ratio between the cross-sectional areas of the first inorganicmicro-particle layer 5 a and the second inorganic micro-particle layer 5b is equal (the ratio thereof is 5:5), the intensity of the leakagelight decreases the most.

In the polarizing element 1 of this embodiment configured as above, thesurface side of the substrate 2, that is, the face side of the substrate2 on which the lattice-shaped reflection layer 3, the dielectric layer4, and the inorganic micro-particle layer 5 are formed becomes a lightincident face. The polarizing element 1 attenuates a polarized wave (TEwave (S wave)) having an electric field component (in the lattice axisdirection, the Y axis direction) that is parallel to the arrangementdirection of the reflection layer 3 and transmits a polarized wave (TMwave (P wave)) having an electric field component (in the directionorthogonal to the lattice, the X-axis direction) vertical to thearrangement direction of the reflection layer 3 by using the fouractions of transmission, reflection, and interference of light andselective light absorption of a polarized wave owing to the opticalanisotropy. In other words, the TE wave is attenuated by the lightabsorbing action of the inorganic micro-particle layer 5. The reflectionlayer 3 serves as a wire grid and reflects the TE wave transmittedthrough the inorganic micro-particle layer 5 and the dielectric layer 4.Here, the TE wave reflected by the reflection layer 3 interferes withthe TE wave reflected by the inorganic micro-particle layer 5 so as tobe attenuated. The TE wave can be selectively attenuated as describedabove.

Method of Manufacturing Polarizing Element

Next, a method of manufacturing a polarizing element will be described.FIGS. 4A to 4E are flow diagrams showing the method of manufacturing apolarizing element. The method of manufacturing a polarizing elementaccording to this embodiment includes: a reflection layer formingprocess in which a plurality of reflection layers arranged in a bandshape at a predetermined interval is formed on a substrate; a dielectriclayer forming process in which a dielectric layer is formed on thereflection layer; and an inorganic micro-particle layer forming processin which inorganic micro-particles having shape anisotropy, in which thelength of the diameter of the micro-particles in the arrangementdirection of the reflection layer is longer than the length of thediameter of the micro-particles in the direction orthogonal to thearrangement direction of the reflection layer, are formed on thedielectric layer, and an inorganic micro-particle layer having convexportions directed toward one adjacent reflection layer side and theother adjacent reflection layer side is formed. The inorganicmicro-particle layer forming process includes: a first inorganicmicro-particle layer forming process in which the first inorganicmicro-particle layer having the first convex portion that is obliquelydirected to one reflection layer side by obliquely forming a film fromthe side of one reflection layer out of adjacent reflection layers isformed; and a second inorganic micro-particle layer forming process inwhich the second inorganic micro-particle layer having the second convexportion that is obliquely directed to the other reflection layer side byobliquely forming a film from the side of the other reflection layer outof the adjacent reflection layers. Hereinafter, the description will bepresented with reference to the drawings.

In the reflection layer forming process shown in FIG. 4A, the reflectionlayers 3 are formed on the substrate 2. For example, the reflectionlayers 3 are formed by pattern processing of a metal film, which isformed from aluminum or the like, using a photolithographic method.

In the dielectric layer forming process shown in FIG. 4B, the dielectriclayers 4 are formed on the reflection layers 3. For example, thedielectric layers formed from SiO₂ or the like are formed by using asputtering method or a sol-gel method.

In the first inorganic micro-particle layer forming process shown inFIG. 4C, the first inorganic micro-particle layer 5 a having the firstconvex portion 10 a that is obliquely directed on the side of onereflection layer 3 out of adjacent reflection layers 3 by obliquelyforming a film from the side of one reflection layer 3. Morespecifically, for example, the first inorganic micro-particle layer 5 ais formed by depositing sputtered particles from a direction inclinedwith respect to the substrate 2 on which the reflection layer is formed.In FIG. 4C, the incident direction of the sputtered particles is denotedby arrows. The oblique angle of the oblique film formation with respectto the substrate 2 face can be appropriately set in the range of about0° to 50°.

In the second inorganic micro-particle layer forming process shown inFIG. 4D, the second inorganic micro-particle layer 5 b having the secondconvex portion 10 b that is obliquely directed to the other reflectionlayer 3 side is formed by obliquely forming a film from the side of theother reflection layer 3 out of adjacent reflection layers 3. In otherwords, the film is formed from the oblique direction that is a directionopposite to the oblique direction of oblique film formation in theabove-described first inorganic micro-particle layer forming process.More specifically, for example, the second inorganic micro-particlelayer 5 b is formed by depositing the sputtered particles from thedirection inclined with respect to the substrate 2 on which thereflection layers 3 are formed using a sputtering device. In FIG. 4D,the incident direction of the sputtered particles is denoted by arrows.The oblique angle of the oblique film formation with respect to thesubstrate 2 face can be appropriately set in the range of about 0° to50°.

In addition, in the first and second inorganic micro-particle layerforming processes, the inorganic micro-particles 50 a that have shapeanisotropy in which the length La of the diameter of the micro-particlesin the arrangement direction of the reflection layer 3 is longer thanthe length Lb of the diameter of the micro-particles in the directionorthogonal to the arrangement direction of the reflection layer 3 areformed on the dielectric layer 4 through the oblique film formation (seeFIG. 1C).

Alternatively, the first inorganic micro-particle layer forming processmay be performed after the second inorganic micro-particle layer formingprocess, or the first and second inorganic micro-particle layer formingprocesses may be simultaneously performed.

Here, in the oblique film formation performed in the above-describedfirst and second inorganic micro-particle layer forming processes, theamounts of sputtered particles to be deposited on the side close to thetarget of the sputtering device and on the side far from the target aredifferent from each other. Thus, the amount of sputtered particles thatare deposited tends to increase as it nears the target. Accordingly, inthe first inorganic micro-particle layer forming process shown in FIG.4C, the volume of the first inorganic micro-particle layer 5 a increasesas it is on a side closer (the negative side in the X axis direction) tothe target of the sputtering device. In contrast, the volume of thefirst inorganic micro-particle layer 5 a decreases as it is on a sidefarther (the positive side in the X axis direction) from the target. Onthe other hand, in the second inorganic micro-particle layer formingprocess shown in FIG. 4D, the volume of the second inorganicmicro-particle layer 5 b increases as it is on a side closer (thepositive side in the X axis direction) to the target of the sputteringdevice. In contrast, the volume of the second inorganic micro-particlelayer 5 b decreases as it is on a side farther (the negative side in theX axis direction) from the target. Thus, although the volumes of each ofthe first inorganic micro-particle layers 5 a and each of the secondinorganic micro-particle layers 5 b are different, the sums of thevolumes of the first and second inorganic micro-particle layers 5 a and5 b corresponding to the reflection layers 3 are the same. Accordingly,the inorganic micro-particle layers 5 having the same total volume areformed on the reflection layers 3. Therefore, balanced opticalcharacteristics can be acquired.

In the protection layer forming process shown in FIG. 4E, the protectionlayers 6 are formed on the first and second inorganic micro-particlelayers 5 a and 5 b. The protection layer 6, for example, is formed withSiO₂ by using a sputtering method or the like. Through theabove-described processes, a polarizing element 1 can be manufactured.

Configuration of Electronic Apparatus

Next, the configuration of an electronic apparatus will be described.FIG. 5 is a schematic diagram showing the configuration of a liquidcrystal projector as the electronic apparatus. The liquid crystalprojector 100 includes a lamp that is a light source, a liquid crystalpanel, a polarizing element 1, and the like.

As shown in FIG. 5, the optical engine part of the liquid crystalprojector 100 includes: an incident-side polarizing element 1A, a liquidcrystal panel 90, an outgoing pre-polarizing element 1B, and an outgoingmain polarizing element 1C for red light LR; an incident-side polarizingelement 1A, a liquid crystal panel 90, an outgoing pre-polarizingelement 1B, and an outgoing main polarizing element 1C for green lightLG; an incident-side polarizing element 1A, a liquid crystal panel 90,an outgoing pre-polarizing element 1B, and an outgoing main polarizingelement 1C for blue light LB; and a cross dichroic prism 60 thatcomposes light output from the outgoing main polarizing elements 1C andallows the composed light to be outgoing to a projection lens (notshown). Here, the polarizing element 1 can be applied to each of theincident-side polarizing elements 1A, the outgoing pre-polarizingelements 1B, and the outgoing main polarizing elements 1C. Inparticular, by applying the polarizing element 1 to the outgoingpre-polarizing element 1B, the contrast can be improved by decreasingthe intensity of leakage light leaking from the outgoing main polarizingelement 1C.

The liquid crystal projector 100 has a configuration in which lightoutgoing from a light source lamp (not shown) is separated into redlight LR, green light LG, and blue light LB by a dichroic mirror (notshown), the separated light is incident to the correspondingincident-side polarizing element 1A, then, the light LR, LG, and LBpolarized by the incident-side polarizing elements 1A is spatiallymodulated by the liquid crystal panel 90 so as to be output and passesthrough the outgoing pre-polarizing element 1B and the outgoing mainpolarizing element 1C, and then, the light is composed by the crossdichroic prism 60 and is projected from the projection lens. Even whenthe light source lamp has a high output level, the polarizing element 1has superior light-resistance characteristics for strong light.Accordingly, a liquid crystal projector having high reliability can beprovided.

In addition, the electronic apparatus including the polarizing element 1is not limited to a liquid crystal projector 100. Other examples includethe polarizing element 1 can be applied to a car navigation device forvehicles, the liquid crystal display of an instrument panel or the like.

Therefore, according to the above-described embodiment, the followingadvantages are acquired.

The polarizing element 1 has the inorganic micro-particle layer 5including the first inorganic micro-particle layer 5 a that is obliquelydirected to one adjacent reflection layer 3 side and has the firstconvex portion 10 a and the second inorganic micro-particle layer 5 bthat is obliquely directed to the other adjacent reflection layer 3 sideand has the second convex portion 10 b. Accordingly, the opticalactivity for the inclined incident light decreases, and the amount ofleakage light can be decreased. In addition, by forming the ratiobetween the cross-sectional areas of the first inorganic micro-particlelayer 5 a and the second inorganic micro-particle layer 5 b so as to beequal, the intensity of leakage light can be further decreased. Byapplying the above-described polarizing element 1 to a liquid crystalprojector 100, a liquid crystal projector 100 that has superior opticalcharacteristics and high contrast can be provided.

The invention is not limited to the above-described embodiment. Thus,the following modified examples may be applied.

MODIFIED EXAMPLE 1

In the above described embodiment, the ratio between the cross-sectionalareas of the first inorganic micro-particle layer 5 a and the secondinorganic micro-particle layer 5 b is formed to be equal (the ratiothereof is 5:5). However, the invention is not limited thereto. Forexample, the ratio of the cross-sectional area of the first inorganicmicro-particle layer 5 a to the cross-sectional area of the secondinorganic micro-particle layer 5 b (the cross-sectional area of thefirstinorganic micro-particle layer 5 a: the cross-sectional area of thesecond inorganic micro-particle layer 5 b) may be configured to be 1:9or 9:1. In other words, the first inorganic micro-particle layer 5 a andthe second inorganic micro-particle layer 5 b may be formed towarddifferent directions. Even in such a case, the intensity of the leakagelight can be decreased by decreasing the optical activity.

MODIFIED EXAMPLE 2

In the above-described embodiment, the cross-sectional area of the firstinorganic micro-particle layer 5 a is fixed at a predetermined value,and the cross-sectional area of the second inorganic micro-particlelayer 5 b is changed. However, it may be configured that thecross-sectional area of the second inorganic micro-particle layer 5 b isfixed at a predetermined value, and the cross-sectional area of thefirst inorganic micro-particle layer 5 a is changed. In other words, thefirst inorganic micro-particle layer 5 a and the second inorganicmicro-particle layer 5 b may be interchanged. Even in such a case, thesame advantages can be acquired.

The entire disclosure of Japanese Application No. 2010-002693, filedJan. 8, 2010 is expressly incorporated by reference herein.

1. A polarizing element comprising: a substrate; a plurality ofreflection layers that is arranged in a band shape at a predeterminedinterval on the substrate; dielectric layers that are formed on thereflection layers; and inorganic micro-particle layers that are formedon the dielectric layers by inorganic micro-particles having shapeanisotropy in which a length of a diameter of the micro-particles in anarrangement direction of the reflection layers is longer than a lengthof a diameter of the micro-particles in a direction orthogonal to thearrangement direction of the reflection layers and has convex portionstoward a side of a first adjacent reflection layer adjacent of onereflection layer and a side of a second adjacent reflection layeradjacent of the one reflection layer.
 2. The polarizing elementaccording to claim 1, wherein the inorganic micro-particle layer has afirst inorganic micro-particle layer that has a first convex portiondisposed on the side of the first adjacent reflection layer and a secondinorganic micro-particle layer that has a second convex portion disposedon the side of the second adjacent reflection layer.
 3. The polarizingelement according to claim 2, wherein, in the cross-sectional vieworthogonal to the arrangement direction of the reflection layers, theratio between cross-sectional areas of the first inorganicmicro-particle layer and the second inorganic micro-particle layer isequal.
 4. A method of manufacturing a polarizing element, the methodcomprising: forming a plurality of reflection layers that is arranged ina band shape at a predetermined interval on a substrate; formingdielectric layers on the reflection layers; and forming inorganicmicro-particles having shape anisotropy in which a length of a diameterof the micro-particles in the arrangement direction of the reflectionlayers is longer than a length of a diameter of the micro-particles in adirection orthogonal to the arrangement direction of the reflectionlayers on the dielectric layers and forming inorganic micro-particlelayers that have convex portions toward a side of a first adjacentreflection layer adjacent of one reflection layer and a side of a secondadjacent reflection layer adjacent of the one reflection layer.
 5. Themethod of manufacturing a polarizing element according to claim 4,wherein the forming of inorganic micro-particle layers comprises:forming a first inorganic micro-particle layer having a first convexportion that is obliquely directed to the side of the first adjacentreflection layer by obliquely forming a film from the side of the firstadjacent reflection layer; and forming a second inorganic micro-particlelayer having a second convex portion obliquely directed to the side ofthe second adjacent reflection layer by obliquely forming a film fromthe side of the second adjacent reflection layer.
 6. An electronicapparatus comprising the polarizing element according to claim
 1. 7. Anelectronic apparatus comprising a polarizing element that ismanufactured by using the method according to claim 4.